Populaire passages

Pagina 39 - The circumference of every circle is supposed to be divided into 360 equal parts, called degrees ; each degree into 60 equal parts, called minutes ; and each minute into 60 equal parts, called seconds.

Pagina 34 - A sphere is a solid, bounded by one continued convex surface, every point of which is equally distant from a point within, called the centre. The sphere may be conceived to be formed by the revolution of a semicircle about its diameter, which remains fixed.

Pagina 95 - Bring the given place to the brazen meridian, and fet the index to the given hour ; then turn the globe, until the place where the hour is required, comes to the meridian ; and the index will point to the hour at that place. PROBLEM VII. Tojind the Suit's Place in the Ecliptic, and his Declination, for any given Day in the Year.

Pagina 27 - ... to suppose that all the fixed stars are placed at the same distance from us ; but it is more probable that they are everywhere interspersed through the vast indefinite space of the universe, and that there may be as great a distance between any two of them as there is between our sun and the nearest fixed star. Hence it follows why they appear to us of different magnitudes, not because they are at different distances from us, those that are nearest excelling in brightness and lustre, those that...

Pagina 40 - ... brought into England from the Netherlands in the year 1524. There are many kinds, hut the two best sorts are the white and grey kind : the latter is a large square hop, more hardy, and is the more plentiful bearer, and ripens later than the other. HORARY circle, of a globe, is fixed upon the brazen meridian, divided into 24 hours, having an index moveable round the axis of the globe, which upon turning the globe 15 degrees, will shew what places have the sun an hour before or after us : and will...

Pagina 152 - Hinges fupport the whole Machine, when it is lifted up, according to any Latitude; and the Arch, at other Times, lies conveniently under the BottomFrame. When the Machine is fet to any Latitude, (which is eafily done by two Men, each taking hold of two Handles, conveniently fixed for...

Pagina 82 - ... the ring or circle in which the artificial globe is suspended by means of the axis ; it is divided into four quadrants, of 90 degrees each. Two of these are' numbered from the equator towards the poles, for the purpose of showing the latitudes of places, or the declinations of the celestial bodies : the other two quadrants are numbered from the poles towards the equator, and are used for elevating the poles of the globe. 106. The CIRCLES on the globe are of two kinds, great and less. GREAT CIRCLES...

Pagina 89 - ... the latitude. Having elevated the globe according to its latitude, count the degrees thereof upon the meridian from the equator towards the elevated pole, and that point will be the zenith, or the vertex of the place ; to this point of the meridian, fasten the quadrant of altitude, so that the graduated edge thereof may be joined to the said point. Having brought the sun's place in the ecliptic to the meridian, set the hour index to XII' at noon, and the globe will be rectified to the sun's place.